Silicone Conformal Coatings

Drones are constantly exposed to moisture and humidity from atmospheric condensation, snow, rain, and dew, which may short out their various circuits and cause malfunction. Fortunately, silicone-based conformal coatings such as MG’s 422B and 422C provide an easy way to protect your drone.  By simply coating the different circuits – the flight controller, speed controllers, camera and so on – you can ensure that the drone will operate even when wet, and can continue its flights uninterrupted. 

It depends on the extent of exposure. If the PCB is simply exposed to ordinary atmospheric moisture or intermittent splashes, a simple and practical solution is to coat the board using a conformal product that meets any additional requirements. For applications with extended moisture exposure or complete submersion, a more aggressive technique such as encapsulation should be considered.

422C is the newest addition to our conformal coating product portfolio. Like 422B, this coating is a silicone/acrylic hybrid coating that dries quickly leaving a smooth film that has a wide operating temperature range. It passed certification testing under the UL746E program as a resist coating from 25 to 75µm.

The 422C product was designed to replace the current 422B conformal coating that has been on the market for many years. While we know 422B has been a highly successful product with much positive feedback, the raw materials used to produce the coating have become more expensive over the years. Therefore, we decided to formulate a new product with similar performance at a lower cost.

Like 422B, 422C uses a blend of silicone and acrylic polymers that gives both the hardness and finish of an acrylic while providing the high temperature protection afforded by silicone. Both coatings are certified as UL94 V-0 under the UL746E designation and are low viscosity that is ready-to-spray. The table below compares properties of 422B with 422C.

	422B	422C
Polymer Composition	Silicone & Acrylic	Silicone & Acrylic
Solvent Composition	Acetone and Aromatics	Acetone and Esters
Dry time to handle	8 Minutes	10 Minutes
Service Temperature (°C)	-40 to 200	-40 to 200
UL94	V-0, 20-30µm	V-0, 25-75µm
Viscosity	10 cP	14 cP
Density	0.90 g/mL	0.92 g/mL
% Solids	28	30